The Victoria and Birrindudu Basins, Victoria River region, Northern Territory, Australia: a SHRIMP U-Pb detrital zircon and Sm-Nd study

Abstract

The Victoria and Birrindudu Basins of the Victoria River region, northwest Northern Territory, represent a pair of stacked unmetamorphosed Paleoproterozoic to Neoproterozoic basins unconformably overlying lowgrade metamorphic basement. SHRIMP U-Pb analysis of detrital zircons provide a basis for lithostratigraphic correlations with other Proterozoic basins across northern Australia. The Paleoproterozoic Stirling Sandstone (basal Limbunya Group is tentatively correlated with the Mount Charles Formation in the Tanami region. The Jasper Gorge Sandstone (basal Auvergne Group) correlates with basal units of the lower Cryogenian Supersequence 1 of the Centralian Superbasin (Heavitree Quartzite and its correlatives). A third correlation, previously proposed elsewhere and further explored here, suggests that the Duerdin Group may correlate with the upper Cryogenian ca 635 Ma Elatina glacigenic units of Supersequence 3 of the Centralian Superbasin. In particular, the Cryogenian pre-glacigenic Black Point Sandstone Member (basal Duerdin Group) is dominated by detrital zircons with age components characteristic of the Musgrave Province, implying significant exhumation and erosion of the Musgrave Province occurred, at least partially, prior to the end of the Cryogenian and far earlier than generally thought. The latter two correlations suggest that the Victoria Basin in the Victoria River region represents yet another relic component of the extensive former Centralian Superbasin, at least during Cryogenian time. Sm-Nd whole-rock determinations overwhelmingly, and unsurprisingly, are consistent with clastic derivation from the evolved North Australian Craton and, for the Black Point Sandstone Member, fromthe Musgrave Province. A relatively juvenile signature is observed coincident with tuffaceous olcanismwithin the Birrindudu Basin at ca 1640 Ma, as has been recently noted in other Australian Paleoproterozoic terrains.